Fabrication method of a semiconductor device

ABSTRACT

To form a wiring electrode having excellent contact function, in covering a contact hole formed in an insulating film, a film of a wiring material comprising aluminum or including aluminum as a major component is firstly formed and on top of the film, a film having an element belonging to 12 through 15 groups as a major component is formed and by carrying out a heating treatment at 400° C. for 0.5 through 2 hr in an atmosphere including hydrogen, the wiring material is provided with fluidity and firm contact is realized.

This is a continuation of U.S. application Ser. No. 08/965,624, filedNov. 6, 1997, U.S. Pat. No. 6,171,961.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention disclosed in the specification relates to a methodof fabricating a semiconductor device having a wiring electrodecomprising aluminum or including aluminum as a major component.

2. Description of the Related Art

In recent years, a necessity of fabricating several millions of largeamount of semiconductor devices on one chip or on the same substrate hasbeen enhanced with high density integration of device elements. Theproblem in fabricating large amount of semiconductor devices is thefabrication yield and operational failure of semiconductor devicesconsiderably lowers the fabrication yield. As one of major causes ofoperational failure of semiconductor devices, contact failure is pointedout.

Contact failure is an operational failure caused when connection failureoccurs at a portion of electrically connecting a wiring electrode and asemiconductor device (hereafter, referred to as contact). Particularly,the contact failure poses a serious problem in view of enhancednecessity of making electrical connection via a slender perforation(contact hole) by the miniaturizing technology and the multi layerwiring technology.

The causes of contact failure are grossly classified into three. Thefirst cause is that a conductive film forming a wiring electrode and asource/drain region (semiconductor film) or a lead out electrode(conductive film) are not brought into ohmic contact with each other.This is due to the fact that an insulating coating, for example, a metaloxide or the like is formed on a contact face.

The second cause is that the coverage of a conductive film forming awiring electrode is poor and disconnection is caused in a contact hole.In this case, improvement must be achieved by film forming method orfilm forming condition of the wiring electrode.

Further, the third cause is disconnection of a wiring electrode causedby the sectional shape of a contact hole or the like. The sectionalshape of a contact hole is strongly dependent on etching conditions ofan insulating material (SiN, SiO₂, organic resin film or the like)covered on the contact portion.

Particularly, contact failure due to the second or the third cause isactualized with a higher aspect ratio of a contact hole by miniaturizinga semiconductor device.

It is an object of the present invention disclosed in the specificationto reduce operational failure of a semiconductor device caused bycontact failure by resolving the above-described problem. Particularly,it is an object of the present invention to provide the technology ofeliminating contact failure when a material comprising aluminum orincluding aluminum as a major component is used as a wiring electrode.

Further, it is an object of the present invention to provide thetechnology of realizing a semiconductor device or an electro-opticdevice having high long period reliability by improving reliability ofcontact. Further, it is an object thereof to promote the yield of thefabrication steps.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, there is provided amethod of fabricating a semiconductor device having a structure having aconductive material and an insulating film formed on the conductivematerial comprising at least a step of forming a contact hole on theinsulating film and exposing the conductive material at a bottomthereof, a step of forming a wiring material comprising aluminum orincluding aluminum as a major component which is brought into electricalcontact with the conductive material at least at the bottom of thecontact hole, a step of forming a film including an element belonging to12 through 15 groups as a major component on a surface of the wiringmaterial, and a step of fluidizing the wiring material by a heatingtreatment wherein the heating treatment is carried out at a temperatureof 400° C. or lower in an atmosphere including hydrogen.

The present invention is constituted by the technology (referred to asreflow technology) improving the coverage in respect of a contact holeby lowering temperatures of fluidizing a wiring material by adding anelement belonging to 12 through 15 groups to the wiring materialcomprising aluminum (Al) or including aluminum as a major component andfluidizing the wiring material by a heating treatment.

Further, the most significant characteristic resides in that the reflowstep can be executed at temperatures of 450° C. or lower, preferably400° C. or lower (representatively 350 through 400° C.) by performingthe heating treatment in an atmosphere including hydrogen. Also, theinventors predict that a reflow operation can be performed even attemperatures lower than 350° C. by optimizing conditions.

The temperature of 350° C. is a temperature that is frequently used inhydrogenation, which is recognized as a temperature preventing analuminum wiring from causing hillocks. Further, the temperature of 400°C. or lower is extremely important in reducing or preventing thermaldeterioration of wirings formed on other layers or insulating films (forexample, organic resin film).

Further, according to the constitution of the present invention, byconstituting a structure sandwiching a conductive film of a titanium(Ti) film or the like between the conductive material and the materialcomprising aluminum or including aluminum as a major component,excellent ohmic contact can be secured.

Further, as the conductive material, material comprising aluminum orincluding aluminum as a major component (for example, material forforming wirings or the like) or a conductive semiconductor material (forexample, semiconductor material for forming source/drain region oftransistor) is representatively pointed out. Naturally, metals such astantalum, tungsten and the like and titanium silicide and the like arealso included in the conductive material.

Further, as an element belonging to 12 through 15 groups utilized as acatalyst in the reflow step, one or a plurality of elements selectedfrom the group consisting of Germanium (Ge), Tin (Sn), Gallium (Ga),Lead (Pb), Zinc (Zn), Indium (In) and Antimony (Sb) are effective.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(A) and 1(B) are photographs for explaining sectional shapes of athin film;

FIGS. 2(A), 2(B); 2(C) and 2(D) are views showing fabrication steps of asemiconductor device;

FIG. 3 is a view showing a structure of a semiconductor device;

FIG. 4 is a view showing a structure of a semiconductor device;

FIGS. 5(A) and 5(B) are views showing a film forming device of a multichamber type; and

FIGS. 6(A), 6(B), 6(C), 6(D), 6(E) and 6(F) are views showingsemiconductor devices as applied products.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A contact hole is formed in respect of an insulating film formed on aconductive material and a titanium film is formed to cover the contacthole. Then, a wiring material comprising aluminum or including aluminumas a major component is laminated on the titanium film.

Furthermore, after forming the wiring material, a film including anelement belonging to 12 through 15 groups as a major component islaminated preferably without being opened to an atmosphere.

Further, a heating treatment at 400° C. (representatively, 350 through400° C.) for 0.5 through 2 hr is carried out in an atmosphere includinghydrogen by which the wiring material is fluidized (reflowed). Thefluidized wiring material covers the contact hole by flowing into thecontact hole and therefore, even if disconnection failure or the like iscaused in the film forming operation, the failure can be improved by thereflow step.

[Embodiment 1]

According to the embodiment, the effect of the reflow step by thepresent invention will be shown by experimental results. FIGS. 1(A) and1(B) show sections at inside of a contact hole where an inner diameterof the contact hole is about 2 μm and a thickness of an interlayerinsulating film is about 0.8 μm. Further, the wiring structure embeddingthe contact hole is constituted by layers of Ti(1000 Å)/Al—Si(5000Å)/Sn(50 Å) in this order from lower layers.

The wiring material (Al—Si) is thickly formed to fabricate a samplecapable of confirming the reflow effect further significantly. Also,formation of the wiring comprising a three layers structure is conductedcontinuously by using a sputtering device of a multi chamber type shownby FIGS. 5(A) and 5(B).

After forming the above-described wiring structure, the reflowprocessing were performed by executing a heating treatment of thepresent invention at 400° C. for 2 hr. FIGS. 1(A) and 1(B) are formed byobserving the section of the contact hole by an SEM (Scanning ElectronMicroscope) in respect of a substrate under the following conditions.

(A) initial state before the reflow step

(B) a state after the reflow step at 400° C. for 2 hr. in an atmosphereof 100% hydrogen.

Firstly, FIG. 1(A) shows the section of the contact hole at the initialstate before the reflow step and in this state, disconnection failure ofthe wiring material is confirmed at the bottom of the contact hole(region at a vicinity of a side wall of the hole).

Next, FIG. 1(B) shows the section of the contact hole after performingthe reflow step at 400° C. for 2 hr. in an atmosphere of 100% hydrogen.As is apparent in FIG. 1(B), it can be confirmed that the shape of thewiring is gently sloping by being made uniform and the contact state ofthe wiring material at inside of the contact hole is extremely improved.

As described above, when FIGS. 1(A) and 1(B) are compared with eachother, it can be understood that the reflow step of the presentinvention is clearly an effective technology in improving disconnectionfailure of the wiring at inside of the contact hole. Further, the factthat the reflow step can be carried out at a temperature of 400° C., hasvery important significance in widening the width of selecting aninsulating film which can be used in a multi layer wiring structure.

Incidentally, although the reason of expediting the fluidization of thewiring is not clearly known when the reflow step is performed under ahydrogen atmosphere, the inventors predict that natural oxides formed onthe surface of the wiring (or film for constituting catalyst) areremoved to a degree whereby the fluidization of the wiring material isnot hampered, owing to the reduction effect of hydrogen.

[Embodiment 2]

According to the embodiment, an example of forming a wiring electrode ofa thin film transistor (TFT) by using the reflow technology according tothe present invention will be described. An explanation will be giventhereof in reference to FIGS. 2(A), 2(B), 2(C) and 2(D).

In FIG. 2(A), numeral 201 designates a substrate having an insulatingsurface and in this embodiment, a silicon oxide film is piled on a glasssubstrate. On top thereof, an activation layer 202 provided bypatterning a crystalline silicon film is arranged. The crystallinesilicon film may directly be formed or formed by crystallizing anamorphous silicon film.

Further, numeral 203 designates a gate insulating film comprising asilicon oxide film and numeral 204 designates a gate electrode includingaluminum as a major component. Numeral 205 designates an anodized filmobtained by anodically oxidizing the gate electrode 204 for protectingthe gate electrode 204.

Next, when the state of FIG. 2(A) is provided, impurity ions (phosphorusor boron) for providing conductive performance are added to theactivation layer 202 in two steps. By these steps, a source region 206,a drain region 207, low concentration impurity regions 208 and 209 and achannel forming region 210 are formed. Especially, the low concentrationimpurity region 209 is referred to as an LDD (Lightly Doped Drain)region.

The technology described in Japanese Unexamined Patent PublicationNumber JP-A-7-135318 by the inventors is utilized in the above-describedfabrication steps. Details thereof will be known by referring to thepublication.

Next, a permeable organic resin material (polyimide in the embodiment)is formed as an interlayer insulating film 211 by a thickness of 1 μm.By using polyimide for the interlayer insulating film, an excellent flatface is obtained by absorbing stepped differences of wirings and thelike. Accordingly, when the wiring material is reflowed in later steps,the film thickness is not extremely thinned at the stepped differences.Further, the reflow step is carried out at 400° C. or lower andtherefore, polyimide is not deteriorated.

Further, a silicon nitride film or a silicon oxide film may be used asthe interlayer insulating film 211. In that case, as the film formingmethod, the plasma CVD (Chemical Vapor Deposition) process or the lowpressure thermal CVD process may be used. Incidentally, when the siliconnitride film is used, it is preferable to form a thin silicon oxide filmat the lowermost layer to constitute an etching stopper in forming thecontact hole in later steps.

Further, when the interlayer insulating film 211 has been formed,contact holes 212 are formed. In this embodiment, the contact holes areformed by the dry etching process. The dry etching process is atechnology indispensable in miniaturization since a contact hole havinga high aspect ratio can be formed by an etching process in use thereof.

A state shown by FIG. 2(B) is provided by the above-described steps.When the state of FIG. 2(B) is obtained, a titanium film 213 is formedon the interlayer insulating film 211 by a thickness of 500 through 1000Å. The titanium film 213 has an effect of making excellent the ohmiccontact between TFT and a wiring electrode.

On top thereof, a wiring material 214 including aluminum as a majorcomponent (alloy of aluminum including scandium, silicon, copper or thelike) is formed by a thickness of 3000 Å. Further, a metal film 215constituted by an element belonging to 12 through 15 groups that isnecessary in the later reflow step, is formed by a thickness of 50through 100 Å. It is preferable that the laminated film is formedcontinuously. Further, the film forming method preferably uses CVDprocess or PVD (Physical Vapor Deposition) process.

Further, it is preferable that the oxygen concentration in the wiringmaterial 214 is 5×10¹⁹ atoms/cm³ or lower, preferably, 1×10¹⁹ atoms/cm³or lower (further preferably, 3×10¹⁸ atoms/cm³ or lower) to efficientlyperform the later reflow step. The oxygen concentration is a valuedefined by a minimum value of measured values of SIMS (Secondary IonMass Spectrometry) analysis.

In the reflow step, oxides on the surface of aluminum constitute afactor for hampering fluidization and therefore, the fluidization of thewiring material may be hampered by the presence of oxygen. Accordingly,it is preferable to reduce as less as possible oxygen included in thewiring material. For that purpose, it is preferable to perform the filmformation of the wiring material 214 in chambers which are cleaned toultra high vacuum.

Further, one or a plurality of kinds of elements constituting the metalfilm 215 selected from the group consisting Ge, Sn, Ga, Zn, Pb, In andSb can be used. According to dual phase diagrams of alloys comprisingthese elements and aluminum, it is known that these elements function ascatalyst elements for lowering a melting point (strictly speaking,fluidizing temperature) of aluminum. Further, it is not necessary thatthe metal film 215 is constituted by a single layer but may have a modeof, for example, a laminated layer of Germanium and Tin.

A state at a time point where the laminated film constituted by theabove-described structure is formed is shown by FIG. 2(C). At thismoment, as shown by FIG. 2(C), since the aspect ratio of the contacthole 212 is high, the wiring material is difficult to form at the inside(particularly, side wall) of the contact hole. Therefore, there is highprobability of causing disconnection failure at the bottom of thecontact hole.

Hence, the reflow step for providing the fluidity to the wiring materialunder this state is executed. The present invention is featured in thatthe reflow step is performed in a hydrogen atmosphere. Further, theprocessing temperature of the reflow step is 400° C. or lower(representatively, 350 through 400° C.) and the processing time is 0.5through 2 hr. In this embodiment, the reflow step is carried out by aheating treatment at 400° C. for 1 hr in a hydrogen atmosphere.

The wiring material 214 is provided with fluidity by the reflow step andthe wiring material 214 can cover effectively the inside of the contacthole. As a result, the wiring material 214 is formed on the side face ofthe contact hole 212 with a sufficient film thickness and disconnectionfailure of the bottom is improved.

Further, the reflow step according to the present invention is carriedout at temperatures of 400° C. or lower and therefore, hillocks orwhiskers can be restrained from occurring on the surface of the wiringmaterial including aluminum as a major component. Furthermore, an effectof hydrogenating the activation layer can be expected in the reflowstep.

The wiring material provided by the above-described reflow step ispatterned by which a source wiring 216, a drain wiring 217 and a gatewiring 218 are formed. Then, a total thereof is hydrogenated by whichTFT having the structure shown by FIG. 2(D) is obtained.

Although an explanation has been given of a method of forming a planartype TFT according to the embodiment, the present invention can becarried out regardless of the structure of TFT. That is, the structureof TFT is not limited to the structure shown by FIG. 2(D) but even with,for example, inverse stagger type TFT or a structure having salicidestructure, the present invention can easily be applied in accordancewith the necessity of a person executing the present invention.

According to TFT formed by utilizing the present invention, thepossibility of contact failure is significantly reduced and highlyreliable operation is realized. The fabrication yield of TFT isconsiderably promoted by utilizing the present invention and therefore,economic merit is enormous.

[Embodiment 3]

This embodiment provides an example when the present invention isapplied to a semiconductor device having a multi layer wiring structure.As an example thereof, FIG. 3 shows a structure when a permeable organicresin material is used as an interlayer insulating film.

FIG. 3 shows a CMOS (Complementary Metal Oxide Semiconductor) circuitwhere an N-channel type TFT 301 and a P-channel type TFT 302 arecomplementarily combined. The fabrication steps of TFT are based onpublicly known technology and therefore, an explanation thereof will beomitted.

In FIG. 3, a first wiring 304 (including all wirings formed in the samelayer) that is brought into direct contact with TFTs 301 and 302, isformed on a first interlayer insulating film 303. First, the presentinvention can be used when the first wiring 304 is formed.

Next, a permeable organic resin material is piled thereon as a secondinterlayer insulating film 305. Further, on top thereof, a second wiring306 is formed. The present invention can be applied also to the secondwiring 306. This has very important significance.

Polyimide, polyamide, polyimide amide or the like is representative as apermeable organic resin material. When a permeable organic resinmaterial is used as an interlayer insulating film, the film thicknesscan be easily increased since the film can be formed by the spinningprocess and further, the throughput can be promoted. Also, a parasiticcapacitance among wirings can be reduced since the relative dielectricconstant is low. However, due to the heat resistance of the permeableorganic resin material, the maximum heating temperature after the filmformation must be restricted to 450° C. or lower (preferably, 400° C. orlower).

However, according to the present invention, the wiring material can bereflowed at 400° C. or lower (representatively, 350 through 400° C.) andtherefore, the reflow step can be carried out with no problem even whenthe permeable organic resin material is utilized as the interlayerinsulating film.

Therefore, the permeable organic resin material is further used as athird interlayer insulating film 307 in FIG. 3 and a third wiring 308 isformed on top thereof by using the present invention, and yet it ispossible to prevent the interlayer insulating films at lower layers fromdeteriorating by heat treatment.

Further, although the example of utilizing the permeable organic resinmaterial as the interlayer insulating film is shown in the embodiment,the same is applicable to the case where a silicon oxide film, a siliconnitride film, a silicon oxinitride film or the like is used as theinterlayer insulating film.

As mentioned above, by utilizing the present invention, a materialhaving low heat resistance can be used as an interlayer insulating filmwhereby the design margin in designing device can be widened.

[Embodiment 4]

The present invention is applicable to an IGFET (Insulated Gate FieldEffect Transistor) formed on a single crystal silicon substrate.Further, the present invention is applicable also to an SOI structurehaving a single crystal silicon as an activation layer.

FIG. 4 shows a structure as an example when a BiCMOS circuit isconstituted as a semiconductor device of a three-dimensional multi layerstructure using an SOI structure. In this case, a CMOS circuit where thelower layer is constituted by a bipolar transistor and the upper layeris constituted by a semiconductor device of an SOI structure, is shown.

In FIG. 4, numeral 401 designates a P-type silicon substrate, numeral402 designates an embedded N⁺ region and numeral 403 designates a p wellformed by epitaxial growth and a p well on the embedded N⁺ region 402constitutes an n well 404 functioning as a collector by being revertedinto N type. Further, numeral 405 designates a DeepN⁺ region forconstituting a lead out electrode led from the embedded N⁺ region 402.Further, numeral 406 designates a field oxidized film formed by thenormal selective oxidation process.

A p⁻ region 407 is firstly formed at the n well 404 for constituting abipolar transistor and successively, a p⁻ region 408 for constituting anexternal base and an n⁺ region 409 for constituting an emitter regionare arranged.

Further, a collector electrode 411, a base electrode 412 and an emitterelectrode 413 are formed by which the bipolar transistor is constituted.The present invention can be applied in forming these electrodes.

The CMOS circuit having the SOI structure in which a single crystalsilicon layer provided by the wafer paste together technology isconstituted as an activation layer, is formed on the bipolar transistorcomprising the above-described constitution. An interlayer insulatingfilm designated by numeral 410 includes a contact face (indicated by adotted line). Here, a detailed explanation of the CMOS circuit will beomitted.

Further, by connecting the CMOS circuit and the bipolar transistor bywirings 414 and 415, the Bi-CMOS structure can be realized. In thiscase, the present invention is applicable to wirings 416 and 417constituting the CMOS circuit, the wirings 414 and 415 for connectingthe CMOS circuit and the bipolar transistor.

As mentioned above, even when the three-dimensional integrated circuitis constituted by utilizing the SOI structure, the reflow process can becarried out without deteriorating other wirings or interlayer insulatingfilms and highly reliable contact can be realized. That is, the presentinvention is an extremely effective technology in fabricating asemiconductor device having a three-dimensional structure.

Further, although an example of constituting the BiCMOS circuit is shownin the embodiment, the present invention is applicable to not only theBiCMOS circuit but a logic circuit of a DRAM (Dynamic Random AccessMemory) circuit, a SRAM (Static Random Access Memory) or the like andhighly reliable VLSI (Very Large Semiconductor Integrated) circuits orULSI (Ultra Large Semiconductor Integrated) circuits can be realized.

[Embodiment 5]

RTA (rapid thermal annealing) can be utilizing as a heating treatmentfor executing the reflow step according to the present invention.

RTA is an annealing process for irradiating intensified light ofinfrared ray, ultraviolet ray or the like by a lamp or the like. As thefeature of this process, a temperature rise rate and a temperature droprate are fast and treatment time is as short as several seconds throughseveral tens seconds and therefore, only a thin film at the topmostsurface can substantially be heated. That is, for example, only a thinfilm on a glass substrate can be annealed at an extremely hightemperature of about 1000° C.

When the RTA technology described in the embodiment is applied, aheating treatment at temperatures exceeding the heat resistance of agate electrode can be executed and therefore, the allowable range of thereflow temperature is widened. Accordingly, the width of selecting metalelements for utilizing in the reflow process can be widened.

Further, the RTA processing can be carried out in an extremely shorttime period of several seconds through several tens seconds andtherefore, it is the effective means also in view of the productivity.

[Embodiment 6]

The present invention has the most significant feature in carrying outthe reflow step in a hydrogen atmosphere and in carrying out a normalheating treatment, hydrogen is existed in a molecular state or an atomicstate. The embodiment shows an example where hydrogen radical orhydrogen ion is used in the reflow step.

For that purpose, plasma is generated in a hydrogen atmosphere and thereflow process is carried out in an atmosphere of excited hydrogen. Byutilizing hydrogen in an activated state by being made radical orionized, the efficiency of the reflow process can be promoted.

Further, the embodiment can be combined with the RTA technologydescribed in Embodiment 5. Thereby, further promotion of throughput canbe expected.

[Embodiment 7]

This embodiment shows an example of using a film forming device having amulti chamber (cluster tool) structure having the constitution shown byFIGS. 5(A) and 5(B) in forming the laminated film constituting thewiring electrodes described in Embodiment 1 or Embodiment 2.

The film forming device having a multi chamber structure shown by FIGS.5(A) and 5(B) is an example of a sputtering device capable ofcontinuously laminating thin films having different compositions(including cases of different elements) at respective reaction chambers.

Here, an explanation will be given of a simple constitution of asputtering device shown by FIG. 5(A). Numeral 10 designates a substrateto be processed, numeral 11 designates a common chamber constituting thedevice main body and numeral 12 designates a transfer mechanism fortransferring the substrate 10. The substrate 10 is transferred in andtransferred out to and from load lock chambers 13 and 14 attached to thedevice main body 11. Further, numerals 15 and 16 designate substratetransfer cassettes installed to the load lock chambers 13 and 14.Further, the load lock chambers 13 and 14 can sealingly be shielded fromthe common chamber 11 by gate valves 17 and 18.

The common chamber 11 is installed with a first reaction chamber 19, asecond reaction chamber 20 and a third reaction chamber 21 and therespectives of the first through the third reaction chambers cansealingly be shielded from the common chamber 11 by gate valves 22, 23and 24. Further, the respectives of the first through the third reactionchambers are provided with vacuum exhaust pumps (not illustrated) whichcan reduce pressure down to ultra high vacuum (1×10⁻⁸ torr or lower,preferably, 1×10 ⁻⁹ torr or lower).

Further, numeral 25 designates a heating chamber which is chamber forperforming the heating treatment in the reflow step. It is preferablethat the heating chamber is provided with a constitution capable ofperforming the RTA processing in consideration of the throughput.Naturally, a plasma generating mechanism may be provided for generatinghydrogen radical described in Embodiment 5. Incidentally, the heatingchamber 25 and the common chamber 11 can also be sealingly shielded fromeach other by a gate valve 26.

Here, FIG. 5(B) shows an outline of a section cut by a broken line inrespect of the sputtering device shown by FIG. 5(A). Incidentally, afurther detailed explanation will be given of a schematic view shown byFIG. 5(A) and therefore, a section of FIG. 5(B) does not necessarilycoincide with a section of FIG. 5(A), however, the explanation will begiven basically of the same sputtering device.

The transfer mechanism 12 arranged in the common chamber 11 is movablein the up and down direction and in the left and right direction andtransfers the substrate 10 to the reaction chambers 19 through 21 or theheating chamber 25. Here, caution is required to the fact that thetransfer mechanism 12 is of a face down type where the substrate 10 isalways transferred with the main surface (face for forming device)directed downwardly. This system is preferable in reducing adhesion ofdirt to the substrate 10. Naturally, a face up system for directing themain surface of the substrate upwardly may be used.

The reaction chamber 21 is constituted by a target support base 31, atarget 32, a shutter 33 and a substrate holder 34. The face down type isadopted in the substrate holder 34 and therefore, it is designed thatonly several millimeters of an end portion of the substrate 10 issupported and the surface of the substrate is not contaminated.Otherwise, the face up type or a type for forming film by verticallyplacing the substrate or the like can be used.

The heating chamber 25 is constituted by a substrate holder 35 andheating lamps 36 and 37. The substrate holder 35 also adopts the facedown type. Further, heating can be carried out from both faces of thesubstrate 10 by the couple of heating lamp 36 and 37. In the case of thedevice, the heating lamp 37 constitutes a main lamp for heating a sideof the main surface. Naturally, the face up type or the like may beused.

Next, an example of forming a laminated structure comprising thin filmshaving different compositions by using the sputtering device constitutedas described above, will be shown.

For example, a first reaction chamber 19 is provided with an Al (orAl—Si, Al—Si—Cu or the like) target, the second reaction chamber 20 isprovided with a Ge (or Sn, Ga or the like) target and the third reactionchamber 21 is provided with a Ti (or TiN or the like) target. Then, aTi—Al—Ge laminated structure or a Ti—Al—Ge—Ti laminated structure or thelike can be provided by carrying out film formation by using therespective targets continuously without being opened to an atmosphere.

Increase or reduction of the number of reaction chambers as necessarycan freely be carried out by a person executing the process and, forexample, a Ti—Al—Ge—Sn laminated structure or the like can be providedby constituting a device having a first through a fourth reactionchamber.

In the reflow step, the surface shape and surface condition of a metalthin film subjected to the reflow process are important factorssignificantly influencing on the reflow step. For example, in anatmosphere, natural oxides are immediately formed on the thin filmsurface including aluminum as a major component and the natural oxidesconstitute a factor for hampering the reflow process. Further, thenatural oxides are insulating and therefore, the natural oxides hamperalso the ohmic contact with other conductive thin films.

However, according to the embodiment, metal thin films having differentcompositions can be laminated without being exposed in an atmosphere andtherefore, the above-described problems are not caused. Particularly,the surface of aluminum is liable to oxidize and therefore, the effectof the embodiment capable of laminating metal thin films without beingopened to an atmosphere is very effective.

[Embodiment 8]

The present invention is applicable to all the semiconductor deviceswhere wiring structures are needed. Hence, the present invention isapplicable to semiconductor devices of an insulating gate typetransistor as well as a thin film diode, a bipolar transistor, athyristor, an electrostatic induction type transistor and the like.

Incidentally, semiconductor devices in the specification are referred toas general devices functioning by utilizing semiconductors and includein the category also electro-optic devices (liquid crystal displaydevice, EL display device, EC display device and the like) of atransmitting type or a reflecting type constituted by variousabove-described semiconductor devices and applied products integratedwith such electro-optic devices.

According to the embodiment, an explanation will be given of the appliedproducts in reference to illustrated examples. As semiconductor devicesutilizing the present invention, a TV camera, a head mount display, acar navigation system, a projection (front type and rear type) system, avideo camera, a personal computer and the like are pointed out. A simpleexplanation will be given in reference to FIGS. 6(A), 6(B), 6(C), 6(D),6(E) and 6(F).

FIG. 6(A) shows a mobile computer which is constituted by a main body2001, a camera unit 2002, an image receiving unit 2003, an operationswitch 2004 and a display device 2005. The present invention is appliedto the display device 2005 and an integrated circuit 2006 integrated inthe inside of the mobile computer.

FIG. 6(B) shows a head mount display which is constituted by a main body2101, a display device 2102 and a band unit 2103. Two sheets having acomparatively small size are used for the display device 2102.

FIG. 6(C) designates a car navigation system which is constituted by amain body 2201, a display device 2202, operation switches 2203 and anantenna 2204. The present invention is applicable to the display device2202 and an integrated circuit at the inside of the device. The displaydevice 2202 is utilized as a monitor in which the resolution of theallowable range is comparably wide since the main purpose of the deviceis display of a map.

FIG. 6(D) is a portable telephone which is constituted by a main body2301, a voice output unit 2302, a voice input unit 2303, a displaydevice 2304, operation switches 2305 and an antenna 2306. The presentinvention is applicable to the display device 2304 and an integratedcircuit at the inside of the device.

FIG. 6(E) shows a video camera, which is constituted by a main body2401, a display device 2402, a voice input unit 2403, operation switches2404, a battery 2405 and an image receiving unit 2406. The presentinvention is applicable to the display device 2402 and an integratedcircuit 2407 at the inside of the device.

FIG. 6(F) shows a front projection system which is constituted by a mainbody 2501, a light source 2502, a reflecting type display device 2503,an optical system (including a beam splitter, a reflector and the like)2504 and a screen 2505. The screen 2505 is a large screen utilized inpresentation at conferences, academic societies and the like andaccordingly, high resolution is required to the display device 2503.

Further, other than the electro-optic devices shown in the embodiment,the present invention is applicable to a rear projection system orportable information terminal devices of handy terminals or the like. Asdescribed above, the range of application of the present invention isextremely wide and the present invention is applicable to display mediain all the fields.

In forming contact for a wiring electrode including aluminum as a majorcomponent, by carrying out a reflow step using an element belonging to12 through 15 groups, firm contact can be formed by the operation of theelement. As a result, excellent contact can be achieved in semiconductordevices of all the structures and the reliability of the semiconductordevices can significantly be promoted.

Further, in that case, the reflow step can be carried out at lowtemperatures of 400° C. or lower, representatively, 350 through 400° C.and therefore, thermal deterioration of wirings of other layers andinsulating films caused by the reflow step can be prevented. Further, infabricating a semiconductor device having a multi layer wiringstructure, the width of selecting material for use of an insulating filmcan be widened.

What is claimed is:
 1. A method of fabricating a semiconductor devicehaving a conductive material and an insulating film formed on saidconductive material, said method comprising the steps of: forming acontact hole in said insulating film and exposing said conductivematerial at a bottom thereof; forming a wiring material in electricalcontact with said conductive material at least at the bottom of saidcontact hole; forming a film comprising an element selected from thegroup consisting of 12 through 15 group elements on said wiringmaterial; and fluidizing at least said wiring material by a heattreatment at a temperature of 400° C. or lower.
 2. A method offabricating a semiconductor device having a conductive material and aninsulating film formed on said conductive material, said methodcomprising the steps of: forming a contact hole in said insulating filmand exposing said conductive material at a bottom thereof; formingtitanium film in contact with said conductive material at least at thebottom of said contact hole; forming a wiring material in contact with asurface of said titanium film; forming a film comprising an elementselected from the group consisting of 12 through 15 group elements onsaid wiring material; and fluidizing at least said wiring material by aheat treatment at a temperature of 400° C. or lower.
 3. A method offabricating a semiconductor device having a conductive material and aninsulating film comprising a resin material formed over said conductivematerial, said method comprising the steps of: forming a contact hole insaid insulating film and exposing said conductive material at a bottomthereof; forming a wiring material in electrical contact with theconductive material at least at the bottom of said contact hole; forminga film comprising an element selected from the group consisting of 12through 15 group elements on said wiring material; and fluidizing atleast said wiring material by a heat treatment at a temperature of 400°C. or lower.
 4. A method of fabricating a semiconductor device having aconductive material and an insulating film comprising a resin materialformed over said conductive material, said method comprising the stepsof: forming a contact hole in said insulating film and exposing saidconductive material at a bottom thereof; forming a wiring material inelectrical contact with said conductive material at least at the bottomof said contact hole; forming a film comprising an element selected fromthe group consisting of 12 through 15 group elements on said wiringmaterial; and fluidizing at least said wiring material by a heattreatment.
 5. A method of fabricating a semiconductor device having aconductive material and an insulating film comprising a resin materialformed over said conductive material, said method comprising the stepsof: forming a contact hole in said insulating film and exposing saidconductive material at a bottom thereof; forming titanium film incontact with said conductive material at least at the bottom of saidcontact hole; forming a wiring material in contact with a surface ofsaid titanium film; forming a film comprising an element selected fromthe group consisting of 12 through 15 group elements on a surface of thewiring material; and fluidizing at least said wiring material by a heattreatment.
 6. A method of fabricating a semiconductor device having aconductive material and an insulating film comprising a resin materialformed over said conductive material, said method comprising the stepsof: forming a contact hole in said insulating film and exposing saidconductive material at a bottom thereof; forming a wiring material inelectrical contact with said conductive material at least at the bottomof said contact hole; forming a film comprising an element selected fromthe group consisting of 12 through 15 group elements on a surface of thewiring material; and fluidizing at least said wiring material by a heattreatment, wherein said heat treatment is carried out by irradiating alight from a lamp.
 7. A method according to any one of claims 1 to 6,wherein the wiring material and the film comprising the elementbelonging to 12 through 15 groups are continuously laminated withoutbeing opened to an atmosphere.
 8. A method according to any one claims 1to 6, wherein said conductive material comprises aluminum or a materialincluding aluminum as a major component or a conductive semiconductormaterial.
 9. A method according to any one claims 1 to 6, wherein saidwiring material comprises aluminum.
 10. A method according to any one ofclaims 1 to 6, wherein said heat treatment is conducted in an atmosphereincluding hydrogen.
 11. A method according to any one claims 1 to 6,wherein said element belonging to 12 through 15 groups is one or aplurality elements selected from the group consisting of Ge, Sn, Ga, Pb,Zn, In, and Sb.
 12. A method according to any one of claims 1 to 2,wherein said insulating film comprises a permeable organic resinmaterial.
 13. A method according to any one of claims 3 to 6, whereinsaid resin material comprises one selected from the group consisting ofpolyimide, polyamide, and polyimide amide.
 14. A method according to anyone claims 1 to 6, wherein said semiconductor device is an EL displaydevice.
 15. A method according to any one of claims 1 to 6, wherein saidsemiconductor device is one selected from the group consisting of amobile computer, a head mount display, a car navigation system, aportable telephone, a video camera, and a projector.
 16. A method toclaim 6, wherein said light comprises an ultraviolet light or aninfrared light.
 17. A method of fabricating an EL display devicecomprising a conductive material and an insulating film formed on saidconductive material, said method comprising the steps of: forming acontact hole in said insulating film and exposing said conductivematerial at a bottom thereof; forming a wiring material in electricalcontact with said conductive material at least at the bottom of saidcontact hole; forming a film comprising an element selected from thegroup consisting of 12 through 15 group elements on said wiringmaterial; and fluidizing at least said wiring material by a heattreatment at a temperature of 400° C. or lower.
 18. A method offabricating an EL display device comprising a conductive material and aninsulating film formed on said conductive material, said methodcomprising the steps of: forming a contact hole in said insulating filmand exposing said conductive material at a bottom thereof; formingtitanium film in contact with said conductive material at least at thebottom of said contact hole; forming a wiring material in contact with asurface of said titanium film; forming a film comprising an elementselected from the group consisting of 12 through 15 group elements onsaid wiring material; and fluidizing at least said wiring material by aheat treatment at a temperature of 400° C. or lower.
 19. A method offabricating an EL display device comprising a conductive material and aninsulating film comprising a resin material formed over said conductivematerial, said method comprising the steps of: forming a contact hole insaid insulating film and exposing said conductive material at a bottomthereof; forming a wiring material in electrical contact with theconductive material at least at the bottom of said contact hole; forminga film comprising an element selected from the group consisting of 12through 15 group elements on said wiring material; and fluidizing atleast said wiring material by a heat treatment at a temperature of 400°C. or lower.
 20. A method of fabricating an EL display device comprisinga conductive material and an insulating film comprising a resin materialformed over said conductive material, said method comprising the stepsof: forming a contact hole in said insulating film and exposing saidconductive material at a bottom thereof; forming a wiring material inelectrical contact with said conductive material at least at the bottomof said contact hole; forming a film comprising an element selected fromthe group consisting of 12 through 15 group elements on said wiringmaterial; and fluidizing at least said wiring material by a heattreatment.
 21. A method of fabricating an EL display device comprising aconductive material and an insulating film comprising a resin materialformed over said conductive material, said method comprising the stepsof: forming a contact hole in said insulating film and exposing saidconductive material at a bottom thereof; forming titanium film incontact with said conductive material at least at the bottom of saidcontact hole; forming a wiring material in contact with a surface ofsaid titanium film; forming a film comprising an element selected fromthe group consisting of 12 through 15 group elements on a surface of thewiring material; and fluidizing at least said wiring material by a heattreatment.
 22. A method of fabricating an EL display device comprising aconductive material and an insulating film comprising a resin materialformed over said conductive material, said method comprising the stepsof: forming a contact hole in said insulating film and exposing saidconductive material at a bottom thereof; forming a wiring material inelectrical contact with said conductive material at least at the bottomof said contact hole; forming a film comprising an element selected fromthe group consisting of 12 through 15 group elements on a surface of thewiring material; and fluidizing at least said wiring material by a heattreatment, wherein said heat treatment is carried out by irradiating alight from a lamp.
 23. A method according to any one of claims 17 to 22,wherein the wiring material and the film comprising the elementbelonging to 12 through 15 groups are continuously laminated withoutbeing opened to an atmosphere.
 24. A method according to any one ofclaims 17 to 22, wherein said conductive material comprises aluminum ora material including aluminum as a major component or a conductivesemiconductor material.
 25. A method according to any one of claims 17to 22, wherein said wiring material comprises aluminum.
 26. A methodaccording to any one of claims 17 to 22, wherein said heat treatment isconducted in an atmosphere including hydrogen.
 27. A method according toany one of claims 17 to 22, wherein said element belonging to 12 through15 groups is one or a plurality elements selected from the groupconsisting of Ge, Sn, Ga, Pb, Zn, In and Sb.
 28. A method according toany one of claims 17 and 18, wherein said insulating film comprises apermeable organic resin material.
 29. A method according to any one ofclaims 19 to 22, wherein said resin material comprises one selected fromthe group consisting of polyimide, polyamide, and polyimide amide.
 30. Amethod according to any one of claims 17 to 22, wherein said EL displaydevice is incorporated in at least one selected from the groupconsisting of a mobile computer, a head mount display, a car navigationsystem, a portable telephone, a video camera, and a projector.
 31. Amethod according to claim 22, wherein said light comprises anultraviolet light or an infrared light.